package org.smart4j.chapter2.helper;

import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.smart4j.chapter2.util.CollectionUtil;
import org.smart4j.chapter2.util.PropsUtil;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Properties;

/**
 * 数据库操作助手类
 */
public final class DatabaseHelper {
    private static final Logger LOGGER= LoggerFactory.getLogger(DatabaseHelper.class);
    private static final QueryRunner QUERY_RUNNER;
    private static final ThreadLocal<Connection> CONNECTION_HOLDER;
    private static final BasicDataSource DATA_SOURCE;
    /*private static final String DRIVER;
    private static final String URL;
    private static final String USERNAME;
    private static final String PASSWORD;*/
    static {
        CONNECTION_HOLDER=new ThreadLocal<Connection>();
        QUERY_RUNNER=new QueryRunner();
        Properties conf= PropsUtil.LoadProps("config.properties");
        /*DRIVER=conf.getProperty("jdbc.driver");
        URL=conf.getProperty("jdbc.url");
        USERNAME=conf.getProperty("jdbc.username");
        PASSWORD=conf.getProperty("jdbc.password");*/
        String driver=conf.getProperty("jdbc.driver");
        String url=conf.getProperty("jdbc.url");
        String username=conf.getProperty("jdbc.username");
        String password=conf.getProperty("jdbc.password");
        DATA_SOURCE=new BasicDataSource();
        DATA_SOURCE.setDriverClassName(driver);
        DATA_SOURCE.setUrl(url);
        DATA_SOURCE.setUsername(username);
        DATA_SOURCE.setPassword(password);
        /*try {
            Class.forName(DRIVER);
        } catch (ClassNotFoundException e) {
            LOGGER.error("can not load jdbc driver", e);
        }*/
    }
    /**
     * 获取数据库连接
     */
    public static Connection getConnection() {
        Connection conn=CONNECTION_HOLDER.get();//每次获取connection时，首先在ThreadLocal中寻找
        if(conn==null) {
            try {
                //conn= DriverManager.getConnection(URL,USERNAME,PASSWORD);
                conn=DATA_SOURCE.getConnection();
            } catch (SQLException e) {
                LOGGER.error("get connection failure",e);
                throw new RuntimeException(e);
            } finally {
                CONNECTION_HOLDER.set(conn);
            }
        }
        return conn;
    }
    /**
     * 关闭数据库连接
     */
    /*public static void closeConnection() {
        Connection conn=CONNECTION_HOLDER.get();
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e){
                LOGGER.error("close connection faiure",e);
                throw new RuntimeException(e);
            } finally {
                CONNECTION_HOLDER.remove();
            }
        }
    }*/
    /**
     * 查询实体列表
     */
    public static <T> List<T> queryEntityList(Class<T> entityClass,String sql,Object... params) {
        List<T> entityList;
        try {
            Connection conn=getConnection();
            entityList=QUERY_RUNNER.query(conn,sql,new BeanListHandler<T>(entityClass),params);
        }catch (SQLException e) {
            LOGGER.error("query entity list failure",e);
            throw new RuntimeException(e);
        } /*finally {
            closeConnection();
        }*/
        return entityList;
    }
    /***
     * 查询实体
     */
    public static <T> T queryEntity(Class<T> entityClass,String sql,Object... params) {
        T entity;
        try {
            Connection conn = getConnection();
            entity=QUERY_RUNNER.query(conn,sql,new BeanHandler<T>(entityClass),params);
        }catch (SQLException e) {
            LOGGER.error("query entity failure",e);
            throw new RuntimeException();
        }
        return entity;
    }
    /**
     * 执行查询语句
     */
    public static List<Map<String,Object>> executeQuery(String sql,Object... params) {
        List<Map<String, Object>> result;
        try {
            Connection conn = getConnection();
            result = QUERY_RUNNER.query(conn, sql, new MapListHandler(), params);
        } catch (Exception e) {
            LOGGER.error("execute query failure", e);
            throw new RuntimeException();
        }
        return result;
    }
    /**
     * 执行更新语句(包括update,insert,delete)
     */
    public static int executeUpdate(String sql,Object... params) {
        int rows=0;
        try {
            Connection conn=getConnection();
            rows=QUERY_RUNNER.update(conn,sql,params);
        }catch (SQLException e) {
            LOGGER.error("execute update failure",e);
            throw new RuntimeException();
        } /*finally {
            closeConnection();
        }*/
        return rows;
    }
    /**
     * 插入实体
     */
    public static <T> boolean insertEntity(Class<T> entityClass,Map<String,Object> fieldMap) {
        if (CollectionUtil.isEmpty(fieldMap)) {
            LOGGER.error("can not insert entity: fieldMap is empty");
            return false;
        }
        String sql="INSERT INTO "+ getTableName(entityClass);
        StringBuilder columns=new StringBuilder("(");
        StringBuilder values=new StringBuilder("(");
        for(String fieldName:fieldMap.keySet()) {//返回此映射中包含的键的 Set 视图。
            columns.append(fieldName).append(", ");
            values.append("?, ");
        }
        columns.replace(columns.lastIndexOf(", "),columns.length(),")");
        values.replace(values.lastIndexOf(","),values.length(),"）");
        sql+=columns+" VALUES "+values;
        Object[] params=fieldMap.values().toArray();
        return executeUpdate(sql,params)==1;
    }
    /**
     * 更新实体
     */
    public static <T> boolean updateEntity(Class<T> entityClass,long id,Map<String,Object> fieldMap) {
        if (CollectionUtil.isEmpty(fieldMap)) {
            LOGGER.error("can not insert entity: fieldMap is empty");
            return false;
        }
        String sql="UPDATE S"+ getTableName(entityClass)+" SET";
        StringBuilder columns=new StringBuilder();
        for(String fieldName:fieldMap.keySet()) {
            columns.append(fieldName).append("=?, ");
        }
        sql+=columns.substring(0,columns.lastIndexOf(", "))+"WHERE id=?";

        List<Object> paramList=new ArrayList<Object>();
        paramList.addAll(fieldMap.values());
        paramList.add(id);
        Object[] params=paramList.toArray();

        return executeUpdate(sql,params)==1;
    }
    /**
     * 删除实体
     */
    public static <T>boolean deleteEntity(Class<T> entityClass,long id) {
        String sql="DELETE FROM "+getTableName(entityClass)+" WHERE id=?";
        return executeUpdate(sql,id)==1;
    }
    private static String getTableName(Class<?> entityClass) {
        return entityClass.getSimpleName();
    }
    /**
     * 执行SQL文件
     */
    public static void executeSqlFile(String filePath) {
        InputStream is=Thread.currentThread().getContextClassLoader().getResourceAsStream(filePath);
        BufferedReader reader=new BufferedReader(new InputStreamReader(is));
        try {
            String sql;
            while((sql=reader.readLine())!=null) {
                executeUpdate(sql);
            }
        } catch (Exception e) {
            LOGGER.error("execute sql file failure",e);
            throw new RuntimeException(e);
        }
    }

}
